Backpack



FIG. 1 is a front and top perspective view of a backpack, showing my new design;

FIG. 2 is a front elevation view thereof;

FIG. 3 is a rear elevation view thereof;

FIG. 4 is a left side elevation view thereof;

FIG. 5 is a right side elevation view thereof;

FIG. 6 is a top plan view thereof;

FIG. 7 is a bottom plan view thereof; and,

FIG. 8 is an enlarged detail view of encircled portion by broken lines in FIG. 1.

The broken lines in the figures illustrate portions of the backpack that form no part of the claimed design. The dash dot dash lines in FIGS. 1, and 8 are for the purpose of depicting the boundary lines of the enlarged views and form no part of the claimed design. 

CLAIM The ornamental design for a backpack, as shown and described. 